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Biomedical subjects

H Mukai

Publications and source records attributed to H Mukai.

At least 127 records · Page 7Linked to original sources
PubMed1995

Pharmacological evidence for neurokinin receptors in murine neuroblastoma C1300 cells.

We found that neurokinin A (NKA) and neurokinin B (NKB) induce an increase in the concentration of intracellular free Ca2+ ([Ca2+]i) in murine neuroblastoma C1300 cells (EC50: NKA 87 +/- 13 nM, NKB 97 +/- 15 nM). Substance P (SP) also caused a transient Ca2+ increase, although the potency of SP was much less than that of NKA and NKB. The increase in [Ca2+]i induced by NKA and NKB was inhibited by SR 48,968, a selective antagonist for NK2, and [beta Ala8]NKA(4-10), a selective agonist for NK2, did not stimulate the increase in [Ca2+]i. NKA- and NKB-induced Ca2+ mobilization was not inhibited by CP-96,345 and [Trp7, beta Ala8]NKA(4-10), selective antagonists for NK1 and NK3, respectively. These results suggested that C1300 cells express endogenous NK2 neurokinin receptors that have different features from known NK2 receptors.

Animals↗
PubMed1995

Endoscopic ultrasonography diagnosis of pancreatic cancer.

Endoscopic ultrasound (EUS) was developed for the detection of small pancreatic cancer because the complete demonstration of the pancreas by conventional ultrasonography (US) was sometimes prevented by intestinal gas and echoic reduction due to the deeper position of the pancreas head and tail. In this article, the diagnosis, staging, limitations, and hazards of EUS for diagnosing pancreatic cancer are described.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1995

[Management of polypoid lesions of the gallbladder by endoscopic ultrasonography (EUS)--a retrospective study to establish the diagnostic criteria and a prospective study to evaluate its reliability].

The diagnostic criteria of endoscopic ultrasonography (EUS) in the management of polypoid lesions of the gallbladder was established by a retrospective study using 57 cases with polypoid lesions of the gallbladder that were all resected and confirmed histologically. By this study, EUS findings of polypoid lesions of the gallbladder were classified into the following six groups; Type I with a foamy high echogram, Type II with a globular high echogram, Type III with a papillary high echogram, Type IV with a papillary solid echogram, Type V with a nodular solid echogram and Type VI with a nodular solid echogram including multiple spotty an-echoic areas which suggested the presence of Rokitansky-Aschoff sinus. Comparing the types of EUS findings with histological diagnosis, Type I and II corresponded to cholesterol polyps. Type III and IV contained benign pseudo tumors such as cholesterol polyp or hyperplastic polyp as well as tumorous lesions such as adenocarcinoma or adenoma. Type III with over 10 mm in size and IV with over 5 mm in size had a possibility of tumorous lesions. Type V usually corresponded to adenocarcinoma, and Type VI to adenomyomatous hyperplasia. From these results, the following criteria was established; (1) Polypoid lesions showing Type I, II, III with less than 10 mm in size, IV with less than 5 mm in size and VI should be followed-up as benign diseases. (2) Polypoid lesions of Type III with over 10 mm in size and IV with over 5 mm in size was considered to be relative indications for surgery as tumors. (3) Polypoid lesions of Type V was an absolute surgical indication as malignant. The reliability of this EUS criteria was followingly evaluated by a prospective study using 94 cases with polypoid lesions of the gallbladder; 32 cases with open or laparoscopic cholecystectomy and 62 cases with over one year follow-up observations. The criteria corresponded well with the histological or follow-up findings in Type I, II, III with less than 10 mm in size, IV with less than 5 mm in size, V and VI. It had, however, a tendency of over indications to surgery in Type III with over 10 mm in size and IV with over 5 mm in size because these types were widely set not to overlook tumorous lesions such as adenoma and small adenocarcinoma.(ABSTRACT TRUNCATED AT 400 WORDS)

Endoscopy, Digestive System↗
PubMed1994

Activation of PKN, a novel 120-kDa protein kinase with leucine zipper-like sequences, by unsaturated fatty acids and by limited proteolysis.

PKN, a novel protein kinase with catalytic domain homologous to PKC family and unique amino terminal leucine zipper-like sequences, was purified partially from COS7 cells transfected with the cDNA construct encoding human PKN for enzymatic characterization of the enzyme. Using serine containing synthetic peptides based on PKC pseudosubstrate sites as the phosphate acceptors, kinase activities estimated from partially purified PKN were not stimulated by Ca2+/phosphatidylserine/diolein but were activated several-fold to several tens-fold by 40 microM unsaturated fatty acids, such as arachidonic acid, linoleic acid, and oleic acid. Autophosphorylation of the immunoprecipitates using anti-PKN antiserum was also stimulated by various unsaturated fatty acids. Limited proteolysis of PKN with trypsin induced an enhancement of the peptide kinase activity that was almost independent of arachidonic acid.

Amino Acid Sequence↗
PubMed1994

Isolation and characterization of CAJ1, a novel yeast homolog of dnaJ.

A novel member of the Escherichia coli dnaJ family, designated CAJ1, was isolated from a yeast expression library using antiserum against a yeast calmodulin-binding fraction. Although CAJ1 contains neither a Gly-rich region nor a Cys-rich repeat, as are found in other DnaJ relatives, it contains a leucine zipper-like motif.

Amino Acid Sequence↗
PubMed1994

A novel protein kinase with leucine zipper-like sequences: its catalytic domain is highly homologous to that of protein kinase C.

A novel protein kinase, designated PKN, was identified by molecular cloning from a human hippocampus cDNA library. PKN consists of 942 amino acids with a calculated molecular mass of 103,925 daltons. PKN has leucine zipper-like sequences in its amino terminal region and contains a catalytic domain that shows strong similarity to that of protein kinase C family. Northern blot analysis indicates PKN is expressed ubiquitously in human tissues. Antisera against PKN identified a 120K dalton protein on SDS polyacrylamide gel electrophoresis when PKN was expressed in the insect cells or COS7 cells. Recombinant PKN revealed an intrinsic protein kinase activity associated with a 120K protein. This activity was abolished by mutation of the lysine residue in the potential ATP binding site.

Amino Acid Sequence↗
PubMed1994

cDNA cloning of an alternatively spliced isoform of the regulatory subunit of Ca2+/calmodulin-dependent protein phosphatase (calcineurin B alpha 2).

A cDNA encoding the regulatory subunit of Ca2+/calmodulin-dependent protein phosphatase, calcineurin B (CNB), was isolated from a rat testis cDNA library. It differs from the cDNA obtained from a rat brain cDNA library by an addition of 138 base pairs in the coding region. The codon of the clone from a testis library corresponding to the initiation codon of the clone from a brain library is not ATG but AAG, 5'-noncoding regions of these cDNAs are also different. The addition in the coding region results in the gain of 46 amino acids at the N-terminus. These findings suggest that two distinct isoforms of CNB alpha are derived from the same gene through a process involving alternative utilization of two promoters. We designate the brain type isoform as CNB alpha 1 and the longer isoform as CNB alpha 2. Northern blot analysis and reverse transcriptase-polymerase chain reaction (RT-PCR) followed by Southern blot analysis suggest that CNB alpha 2 is specifically expressed in the testis, and its expression is developmentally regulated.

Amino Acid Sequence↗
PubMed1994

Shape memory alloy catheter system for peroral pancreatoscopy using an ultrathin-caliber endoscope.

Two types of a shape memory alloy (SMA) catheter system with a mechanism for tip control and irrigation were evaluated in performing peroral pancreatoscopy (PPS) using an ultrathin-caliber endoscope. The selective cannulation of SMA catheters into the papilla was made possible in 18 of 19 patients with pancreatic diseases. Endoscopic sphincterotomy was necessary in six of seven patients with the two-directional catheter (2.6 mm) but in only one of 12 patients examined with the one-directional type (2.2 mm). In 17 of the 18 patients, the catheters were smoothly advanced to the desired positions in the main pancreatic duct, even to the distal pancreas, due to their controllable tip. PPS with adequate inspection of the ducts and lesions was successful in 16 of these 17 patients. Features of cancer (duct disruption, tumor infiltration) and chronic pancreatitis (smooth ductal surface, fine vascular network) could be distinguished. In this series, there were no obvious complications during or after the procedure. In our experience, the SMA catheter system is effective for PPS in patients with an intact papilla and without dilation of the main pancreatic duct. Further study will show the clinical benefits this technique may have in pancreatic diseases.

Alloys↗
PubMed1994

Detection of alcohol-tolerant hiochi bacteria by PCR.

We report a sensitive and rapid method for detection of hiochi bacteria by PCR. This method involves the electrophoresis of amplified DNA. Nucleotide sequences of the spacer region between 16S and 23S rRNA genes of 11 Lactobacillus strains were identified by analysis of PCR products. Five primers were designed by analysis of similarities among these sequences. A single cell of Lactobacillus casei subsp. casei could be detected when purified genomic DNA was used as the template. When various cell concentrations of L. casei subsp. casei were added to 50 ml of pasteurized sake and the cells were recovered, the detection limit was about one cell. No discrete band was observed in electrophoresis after PCR when human, Escherichia coli, mycoplasma, Acholeplasma, yeast, or mold DNA was used as the template.

Bacteriological Techniques↗
PubMed1994

Histopathology of canine hearts subjected to catheter ablation using radiofrequency energy.

To investigate the pathologic changes of the myocardium and the adverse effects of radiofrequency (RF) catheter ablation, we observed canine hearts that had been ablated by RF energy. Catheter ablation was administered to three sites of the hearts of 46 dogs: endomyocardium, coronary sinus, and atrioventricular junction. The dogs were sacrificed 0-12 weeks after ablation and the lesions were stained with hematoxylin-eosin and Azan stain. Each ablated lesion was well demarcated from the adjacent normal tissue. The margin between the ablated lesion and normal tissue became clearer with time. The lesions were hemispherical and measured about 2 to 10 mm in diameter and 1 to 6 mm in depth. Histologic examination in the acute phase demonstrated the presence of coagulation necrosis of the myocardium, interstitial hemorrhage and edema, followed by infiltration of inflammatory cells. Granulation tissue replaced the normal myocardium. In the chronic phase, the lesions became fibrotic and fatty. A mural thrombus was found in 30% of the cases of endomyocardial ablation and 50% of the right ventricular lesions were transmural. Ablated lesions in the coronary sinus extended to the left atrium and left ventricle. Obstruction of the coronary sinus was observed in 8% of the ablated dogs. Most of the lesions with complete atrioventricular block were ablated at the His penetrating region of the conduction system. Thus, since the ablated lesions were clearly delineated, catheter ablation using RF energy appears to eliminate only the target area.

Animals↗
PubMed1994

[Suppression of myoclonus associated with intermittent photic stimulation (IPS) in a case of Creutzfeldt-Jacob disease: with special reference to the specificity of IPS frequency].

The present study deals with electrophysiological findings 3 months after the patient fell into an apallic state during the course of Creutzfeldt-Jacob disease (CJD), when periodic limb myoclonus synchronizing with periodic synchronous discharge (PSD) began to diminish. The findings were as follows: On 2 Hz intermittent photic stimulation (IPS), myoclonus and the diffuse bisynchronous high amplitude sharp wave showed dissociation; the myoclonus was completely suppressed, while the high amplitude sharp wave was elicited. On 3 Hz IPS, myoclonus was incompletely suppressed, corresponding to every other high amplitude sharp waves which were induced synchronous to IPS. On 1 Hz IPS, the high amplitude sharp waves were scarcely induced while neither PSD nor the myoclonus were suppressed. The frequency of the PSD was about 1.2 Hz. Based on these findings, we propose that in addition to the cortical refractory period after PSD or the giant response to photic stimulation, there must be another refractory period in the distal impulse pathway longer than the cortical one. Although the exact electrophysiological mechanism involved in the present findings remains unknown, the possible mechanism responsible for the suppression of myoclonus by IPS and the specificity of IPS frequency in the suppression could be due to competitive suppression of the impulse between periodic myoclonus and the cortical reflex myoclonus through the interaction of the two independent refractory periods in the transmission pathway of the impulse.

Aged↗
PubMed1994

[Correlation between fetal growth and platelet function in normal pregnancy].

Various interpretations have been attempted, but no definitive theory has yet been established as to the etiology of the low-birth-weight infant. We carried out the present study in an attempt to explore the relationship between platelet functions and fetal growth during normal pregnancy. For this purpose, we made a retrospective study of 130 pregnant women aged 23-35 with no clinical abnormalities throughout pregnancy or at delivery. Blood samples were taken at 29-30 weeks of gestation (referred to as the 2nd trimester) and 37-38 weeks of gestation (referred to as the 3rd trimester). The cases studied were divided into two groups: i) those with a birth weight of under 2,500g (n = 32), and ii) those with a birth weight of over 2,500g (n = 98). In these two groups, we studied the platelet functions in maternal blood in the 2nd and 3rd trimesters. The following results were obtained: 1) In the 2nd to 3rd trimester, the platelet count showed no significant variation with the birth weight. 2) In the 2nd to 3rd trimester, the platelet aggregation was found to be moderately depressed in cases with a birth weight of under 2,500g, while it was found to be moderately activated in cases with a birth weight of over 2,500g. 3) In the 2nd to 3rd trimester, platelet factor 4 was significantly lower (p < 0.005) in cases with a birth weight of under 2,500g, while it was moderately higher in cases with a birth weight of over 2,500g.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗